How to fix it, depends on what's broken, I'd say. If you don't have a service contract for it the best thing to do is call HP and arrange a repair.
How to configure a consumer grade router is detailed in the manual that came with it. For a professional router it might be better to have it done by the supplier.
Do I understand your company has a vacancy for an IT-guy? Or maybe they'd better outsource the system management.
Okay, I know this is a rather dull question. I work for an oil company call Gulf Coast Western. I'm trying to figure out how to fix a hewlett packard printer that also dubs as a scanner. The printer / scanner services 3 workstations. Not even sure how to configure our office router. Can somebody help?